Moisture sensor

ABSTRACT

A moisture sensor comprises a carrier element comprises an insulating material, a first and a second electrode structure at a distance from one another at the carrier element, a moisture-sensitive, dielectric layer element at a first main surface region of the carrier element and adjacent to the first and second electrode structures and a third electrode structure on a first main surface region of the moisture-sensitive, dielectric layer element, such that the moisture-sensitive, dielectric layer element is between the third electrode structure and the first electrode structure and between the third electrode structure and the second electrode structure. The first electrode structure is a first capacitor electrode and the second electrode structure is a second capacitor electrode of a measurement capacitor for capacitive moisture measurement, wherein the third electrode structure is a floating electrode structure.

This application claims the benefit of German Application No.102018215018.4, filed on Sep. 4, 2018, which application is herebyincorporated herein by reference.

TECHNICAL FIELD

Exemplary embodiments relate to a moisture sensor and to a method forproducing same. In particular, exemplary embodiments relate to avertical leakage field moisture sensor or a concept for detectingmoisture by a vertical component of the electrical leakage field.

BACKGROUND

The detection of environmental or ambient parameters in the surroundingatmosphere is becoming more and more important in the implementation ofa corresponding sensor system within mobile devices, but also in theapplication in home automation, such as e.g., Smart Home, and forexample also in the automotive sector. As the use of sensors becomesmore and more comprehensive, however, there is in particular also a needto be able to produce such sensors with as little complexity as possibleand thus as cost-effectively as possible, but the resulting reliabilityand accuracy of the sensors ought nevertheless to be maintained.

SUMMARY

There is thus a need for a concept for reliable moisture sensors which,on the one hand, detect the moisture or air humidity in the surroundingatmosphere as reliably and accurately as possible and, on the otherhand, can also be integrated into existing semiconductor processingprocesses with as little complexity as possible.

Such a need can be met by the subject matter of the independent patentclaims. Developments of the present concept are defined in the dependentclaims.

In accordance with one exemplary embodiment, a moisture sensor 100comprises a first and a second electrode structure 102, 104, amoisture-sensitive, dielectric layer element 106, and an insulationstructure 108 having a cutout 110 having a sidewall region 110-1 and abottom region 110-2. The moisture-sensitive, dielectric layer element106 is arranged in the cutout 110 and at least partly fills the latter,wherein the first electrode structure 102 is arranged adjacent to thewall region 110-1 of the cutout 110 at least partly in the insulationstructure 108, wherein the second electrode structure 104 is arrangedadjacent to the bottom region 110-2 of the cutout 110 at least partly inthe insulation structure 108, and wherein the first electrode structure102 is configured as a first common capacitor electrode and the secondelectrode structure 104 is configured as a second common capacitorelectrode of a measurement capacitor 102, 104 for capacitive moisturemeasurement.

In accordance with one exemplary embodiment, the moisture-sensitive,dielectric layer element 106 is configured to be effective at leastregionally as a capacitor dielectric of the measurement capacitorbetween the first and second capacitor electrodes 102, 104.

In accordance with one exemplary embodiment, a moisture sensor 200comprises a carrier element 208 comprising an insulating material, afirst and a second electrode structure 202, 204 arranged at a distancefrom one another at the carrier element 208, a moisture-sensitive,dielectric layer element 206 at a first main surface region 208-1 of thecarrier element 208 and adjacent to the first and second electrodestructures 202, 204, and a third electrode structure 210 on a first mainsurface region 206-1 of the moisture-sensitive, dielectric layer element206, such that the moisture-sensitive, dielectric layer element 206 isarranged between the third electrode structure 210 and the firstelectrode structure 202 and between the third electrode structure 210and the second electrode structure 204. In this case, the firstelectrode structure 202 is configured as a first capacitor electrode andthe second electrode structure 204 is configured as a second capacitorelectrode of a measurement capacitor 202, 204 for capacitive moisturemeasurement, wherein the third electrode structure 210 is configured asa floating electrode structure.

In accordance with one exemplary embodiment the moisture-sensitive,dielectric layer element 206 is configured to be effective at leastregionally as a capacitor dielectric of the measurement capacitor.

In accordance with one exemplary embodiment the floating electrodestructure 210 comprises a conductive layer having openings 210-A, suchthat the moisture-sensitive, dielectric layer element 206 is accessibleto the surrounding atmosphere through the openings 210-A.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred exemplary embodiments of the present concept of a moisturesensor are explained in greater detail below with reference to theaccompanying drawings, in which:

FIGS. 1a-1c show basic schematic cross-sectional illustrations of a(vertical) moisture sensor in accordance with one exemplary embodiment;

FIG. 1d shows a schematic cross-sectional illustration of the sensorregion of the moisture sensor with a basic illustration of the resultingcapacitive equivalent circuit diagram in accordance with one exemplaryembodiment;

FIG. 2a shows a basic schematic cross-sectional illustration of amoisture sensor in accordance with a further exemplary embodiment;

FIG. 2b shows a schematic cross-sectional illustration of the sensorregion of the moisture sensor with a basic illustration of the resultingcapacitive equivalent circuit diagram in accordance with a furtherexemplary embodiment;

FIGS. 3a-3c show basic schematic cross-sectional illustrations of amoisture sensor in accordance with a further exemplary embodiment;

FIG. 3d shows a schematic cross-sectional illustration of the sensorregion of the moisture sensor with a basic illustration of the resultingcapacitive equivalent circuit diagram in accordance with a furtherexemplary embodiment;

FIGS. 4a-4c show basic schematic cross-sectional illustrations of themoisture sensor in accordance with a further exemplary embodiment;

FIG. 4d shows a schematic cross-sectional illustration of the sensorregion of the moisture sensor with a basic illustration of the resultingcapacitive equivalent circuit diagram in accordance with a furtherexemplary embodiment;

FIGS. 5a, 5c show basic schematic cross-sectional illustrations of amoisture sensor in accordance with a further exemplary embodiment;

FIG. 5b shows a basic schematic 3D illustration of a moisture sensor inaccordance with one exemplary embodiment;

FIG. 5d shows a schematic cross-sectional illustration of the sensorregion of the moisture sensor with a basic illustration of the resultingcapacitive equivalent circuit diagram in accordance with one exemplaryembodiment;

FIG. 6 shows a basic flow diagram of a method or process sequence forproducing a moisture sensor in accordance with one exemplary embodiment;

FIG. 7 shows a basic flow diagram of a method or process sequence forproducing a moisture sensor in accordance with a further exemplaryembodiment; and

FIG. 8 shows a basic flow diagram of a method or process sequence forproducing a moisture sensor in accordance with a further exemplaryembodiment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Before exemplary embodiments of the present concept are explained morespecifically in detail below with reference to the drawings, it ispointed out that identical, functionally identical or identically actingelements, objects, function blocks and/or method steps are provided withthe same reference signs in the various figures, such that thedescription of said elements, objects, function blocks and/or methodsteps that is presented in various exemplary embodiments is mutuallyinterchangeable or can be applied to one another.

Various exemplary embodiments will now be described more thoroughly withreference to the accompanying drawings illustrating some exemplaryembodiments. In the figures, dimensions of layers and/or regions may beillustrated in a manner not to scale for elucidation purposes.

It goes without saying that if one element is designated as “connected”or “coupled” to another element, it can be connected or coupled directlyto the other element or intermediate elements can be present. If, incontrast, one element is designated as “connected” or “coupled”“directly” to another element, no intermediate elements are present.Other expressions used for describing the relationship between elementsshould be interpreted in a similar way (e.g., “between” vis-à-vis“directly between”, “adjacent” vis-à-vis “directly adjacent”, etc.).

In order to simplify the description of the geometric arrangement of themoisture sensor and of the elements forming the moisture sensor, aCartesian coordinate system is furthermore indicated in the figures,wherein the x-axis and the y-axis lie in the plane of the drawing, andthe z-axis extends perpendicular thereto into the plane of the drawing.

The basic construction and the general functioning of a moisture sensor100 in accordance with one exemplary embodiment will now be described byway of example below with reference to FIGS. 1a -1 d.

As is illustrated with reference to the basic schematic cross-sectionalillustration in FIG. 1a , the moisture sensor 100 comprises a first anda second electrode structure 102, 104, a moisture-sensitive, dielectriclayer element 106 and an insulation structure 108. The insulationstructure 108 is formed by a cutout 110 having a (for examplecircumferential) sidewall region 110-1 and a bottom region 110-2. As isillustrated in FIG. 1a , the moisture-sensitive, dielectric layerelement 106 is arranged in the cutout 110 and at least partly fills saidcutout 110. In the exemplary illustration in FIG. 1a , themoisture-sensitive, dielectric layer element 106 completely fills thecutout 110, and is embodied flush with an upper main surface region108-A of the insulation structure 108 for example at a surface region106-A of the layer element.

As will additionally be made clear by the following explanationsreferring to FIGS. 1b and 1c , this configuration should be assumed tobe merely by way of example, wherein different geometric configurationsof the moisture-sensitive, dielectric layer element 106 in the cutout110 and optionally at the upper main surface region 108-A of theinsulation structure 108 can be implemented.

As is illustrated in FIG. 1a , the first electrode structure 102 isarranged e.g., laterally (=in the x-direction) adjacent to the wallregion 110-1 of the cutout 110 and is at least partly or else completelyarranged in the material of the insulation structure 108 or embeddedtherein. The second electrode structure 104 is then arranged e.g.,vertically (=in the y-direction) adjacent to the bottom region 110-2 ofthe cutout 110, and is at least partly or else completely arranged inthe material of the insulation structure 108 or embedded therein.Consequently, the first electrode structure 102 is configured as acommon capacitor electrode and the second electrode structure 104 isconfigured as a second common capacitor electrode of a measurementcapacitor 102, 104 having the total capacitance C_(G) for capacitivemoisture measurement.

The total capacitance C_(G) is able to be tapped off via contactconnection regions 114, 116, for example, wherein the first contactconnection region 114 is connected to the first electrode structure 102,and wherein the second contact connection region 116 is connected to thesecond electrode structure 104.

As is illustrated in FIG. 1a , the first electrode structure 102 can beconnected to a common, first potential V₁, while the second electrodestructure 104 can be connected to the second potential V₂, where V₁≠V₂,in order to apply a potential difference ΔV=V₁−V₂ between the first andsecond electrode structures 102, 104, i.e., across the measurementcapacitor 102, 104 having the total capacitance C_(G). As is evidentfrom FIG. 1a , then, the moisture-sensitive, dielectric layer element106 is arranged in the cutout 110 between the first and second capacitorelectrodes 102, 104 in such a way as to be effective at least regionallyas a capacitor dielectric of the measurement capacitor.

The moisture-sensitive, dielectric layer element 106 is configured,then, to have a relative permittivity ε_(r) dependent on the relative orabsolute moisture in the surrounding atmosphere. The moisture-sensitive,dielectric layer element 106 can comprise a polyimide material, forexample. All electrically insulating materials whose relativepermittivity is moisture-dependent are suitable, in principle.

The moisture sensor 100 is designed, then, in the event of a potentialdifference ΔV=V₁−V₂ being applied between the first and second capacitorelectrodes 102, 104 of the measurement capacitor, to provide or to beable to read out a capacitance value C_(G) dependent on the (relative orabsolute) moisture in the surrounding atmosphere.

Further possible configurations or implementations of the individualelements of the moisture sensor 100 will now be illustrated by way ofexample below with reference to FIGS. 1b and 1c in a basic schematiccross-sectional illustration of the moisture sensor 100.

As is illustrated in FIG. 1b , the moisture-sensitive, dielectric layerelement 106 can also be arranged above the upper surface regions 108-Aof the insulation structure 108 and completely fills the cutout 110. Asis furthermore illustrated in FIG. 1b , a carrier element or substrate112 can be provided, wherein the second electrode structure 104 arrangedin a manner adjoining the bottom region 110-2 of the cutout 110 isarranged between the insulation material of the insulation structure 108and the carrier element 112. As is furthermore illustrated in FIG. 1b ,the second electrode structure 104 can be arranged as a buried electrodestructure 104 between the carrier element 112 and the insulationstructure 108. As is illustrated by way of example in FIG. 1b , thesecond electrode structure 104 can also be completely embedded in thematerial of the insulation structure 108, such that the material of theinsulation structure 108 is also situated between the second electrodestructure 104 and the carrier element 112.

As is furthermore illustrated by way of example in FIG. 1b , the firstand second electrode structures 102, 104, e.g., apart from the contactconnection regions or contacting regions (e.g., edge regions) 114, 116,can be at least regionally or else completely embedded in or surroundedby the insulation material of the insulation structure 108.

In accordance with an alternative embodiment (not illustrated in FIG. 1b), the second electrode structure 104 can also be configured as ametallization structure directly on the upper surface region 112-1 ofthe carrier element 112, wherein in this case for example the carrierelement 112 itself can then also comprise an electrically insulatingmaterial.

As is evident in FIG. 1b , some dimensions of individual elements of themoisture sensor 100 are then illustrated by way of example therein,wherein the illustrated dimensions or dimension ranges can also vary,e.g., by a factor of 3, in other applications.

As is illustrated by way of example in FIG. 1b , that section of thefirst electrode structure which extends adjacent to the wall region110-1 can have a height h₁₀₂ of 0.5 μm±20% (or between 0.1 μm and 2 μmor between 0.2 μm and 1 μm) and a width b₁₀₂ of 0.25 μm±20% (or between0.05 μm and 1 μm or between 0.1 μm and 0.5 μm). The cutout can have forexample a width b₁₁₀ of 0.1 μm to 20 μm (or of 0.5 μm to 5 μm or of 1 to3 μm) and a height h₁₁₀ of 0.1 μm and 10 μm (or of 0.5 μm and 3 μm or of1.1 μm to 1.6 μm). The vertical distance a_(v) between the first andsecond electrode structures 102, 104 can be for example between 0.05 μmand 10 μm (or between 0.2 μm and 2 μm or between 0.5 μm and 1 μm).Furthermore, the insulation structure 108 surrounding the firstelectrode structure 102 can have a thickness d₁₀₈ of approximately 0.1μm±20% (or between 0.01 μm and 1 μm or between 0.05 μm and 0.5 μm). Ifan insulation material is provided between the carrier element(substrate) 112 and the second electrode structure 104, the thicknessd₁₁₂ can be between 1 μm and 50 μm (or between 2 μm and 20 μm or betweenapproximately 5 and 10 μm).

With regard to the dimensions or dimension ranges illustrated in FIG. 1b, it is pointed out that they should be assumed to be merely by way ofexample for a possible embodiment of the moisture sensor 100, wherein inaccordance with the present principle of action of the moisture sensor100, of course, other dimensions or dimension ratios can also be usedand furthermore the functionality of the moisture sensor 100 is equallymaintained.

FIG. 1c then illustrates a different configuration of themoisture-sensitive, dielectric layer element 106 in a basic schematiccross-sectional illustration of the moisture sensor 100. In contrast tothe illustration of the moisture-sensitive, dielectric layer element 106from FIG. 1b , in the configuration illustrated in FIG. 1c , thedielectric layer element 106 is configured as a “lining” of the cutout110, wherein the moisture-sensitive, dielectric layer element 106 coversthe wall regions 110-1 and the bottom region 110-2 (at least regionallyor else completely) with a relatively uniform layer thickness d₁₀₆. Thedielectric layer element 106 can thus be configured as a “conformal”coating of the sidewall regions and the bottom region 110-1, 110-2 ofthe cutout 110. This for example U-shaped or trough-shaped configurationof the moisture-sensitive, dielectric layer element 106 within thecutout 110 results in an increased or enlarged interaction area(=exposed surface area) of the material of the dielectric layer element106 with the surrounding atmosphere and with the moisture containedtherein. As a result, it is possible to increase the response behaviorof the moisture sensor 100 in response to a change in the moisture inthe surrounding atmosphere, since e.g., by comparison with thecompletely filled configuration from FIG. 1a it is possible to obtain alarger interaction area of the moisture-sensitive, dielectric layerelement 106. This thus results in a faster response of the moisturesensor 100 to a change in moisture.

By way of the thickness d₁₀₆ of the material of the moisture-sensitive,dielectric layer element 106, it is thus possible to set firstly theresponse behavior and secondly the achievable signal-to-noise ratio ofthe moisture sensor 100 by providing the largest possible interactionarea of the active layer element 106 with the surrounding atmosphere andfurthermore the highest possible permeation of the active layer element106 by the electric field lines between the first and second electrodestructures 102, 104.

As is furthermore illustrated as optional in FIG. 1c , themoisture-sensitive, dielectric layer element 106 configured as aconformal coating can e.g., also extend onto the upper surface region108-A of the insulation structure 108. The optional region of theinsulation structure 108 on the upper surface region 108-A isillustrated in a hatched manner in FIG. 1 c.

With reference to FIG. 1d in the form of a schematic cross-sectionalview, a description will now be given below of the sensor region of themoisture sensor 100 with a basic illustration of the resultingcapacitive equivalent circuit diagram on account of the distribution ofthe electric field between the first and second electrode structures102, 104.

As described above, given a potential difference ΔV between the firstand second potential connections V₁, V₂, an electric field E havingelectric field lines forms between the first and second electrodestructures 102, 104.

As is evident from FIG. 1d , the portions C__(m1), C__(m2) and C__(m3)contributing to the measurement capacitance C__(M) arise on account ofthe electric field lines passing through the moisture-sensitive,dielectric layer element 106 between the first and second electrodestructures 102, 104, while the parasitic capacitances C__(P), which donot contribute to the measurement, represent the field lines passingbetween the first and second electrode structures 102, 104 withoutpassing through the moisture-sensitive, dielectric layer element 106.

The higher the electric flux density of the electric field E between thefirst and second electrode structures 102, 104 in themoisture-sensitive, dielectric layer element 106, the higher the portionof the measurement capacitance C__(M) (C__(m1), C__(m2) and C__(m3)) andthe lower the portion of the parasitic capacitance C__(P) (i.e., theportion which does not contribute to the measurement) in the totalcapacitance C_(G) of the moisture sensor 100. It is thus possible toachieve a high resultant measurement signal on the basis of the portionC__(M) dependent on the ambient moisture in the total capacitance C_(G)of the moisture sensor 100 and thus a high signal-to-noise ratio (SNR)of the moisture sensor 100.

The ratio of the measurement capacitance C__(M) relative to theparasitic capacitance C__(P) thus represents the ratio between theelectric field lines passing between the first and second electrodestructures 102, 104 within the moisture-sensitive, dielectric layerelement 106 (=contribution to the measurement capacitance C__(M)) andthose passing outside the moisture-sensitive, dielectric layer element106 (=contribution to the parasitic capacitance C__(P)).

The moisture sensor 100 can be implemented in various ways. In thisregard, the moisture sensor 100 can be arranged for example as aso-called “stand-alone” component or else on a BEOL stack (BEOL=back-endof line) as a single component or else in a group of sensor components.

In the configuration of the moisture sensor 100 for example as astand-alone component, the carrier element 112 can be configured as asubstrate comprising for example an electrically nonconductive material,such as e.g. Si_(x)N_(y) or SiO_(x). In the configuration of themoisture sensor 100 on a BEOL stack, the carrier element 112 can be ametal layer or metal plane of the BEOL stack.

In order to elucidate the term “BEOL stack”, it is explained by way ofexample that such a BEOL stack is arranged on a semiconductor substrate(not shown in FIGS. 1a-1d ). Such a semiconductor substrate can be forexample a semiconductor wafer, such as a silicon wafer, for example,processed in an FEOL process (FEOL=front-end of line) and optionallycomprise an integrated circuit arrangement or an ASIC(ASIC=application-specific integrated circuit) or generally CMOScomponents, for example, wherein the BEOL layer stack is then applied tothe semiconductor wafer in the BEOL process. The BEOL layer stack (alsocalled wiring layer stack) is provided, for example, in order to providefor the FEOL components connection structures, i.e., predefinedconnections among FEOL components and/or connections to terminalcontacts at the top side of the layer stack. The metallizationstructures of the BEOL layer stack comprise for example a metal or ametal alloy, such as e.g., copper, aluminum, etc., and are embedded intoan insulation material. These explanations with regard to a BEOL stackshould only be taken into consideration, however, provided that thecarrier element 112 is part of such a BEOL stack.

The insulation structure 108 can be configured for example as apassivation layer structure comprising a passivation material, such ase.g., silicon nitride or an oxide material, e.g., SiO_(x), wherein theinsulation material or passivation material of the insulation structure108 provides for or effects an electrical decoupling of the first andsecond electrode structures 102, 104.

The cutout 110 in the insulation or passivation layer structure 108 canfor example be in the shape of a trench, i.e., elongate, or have (as asectional view in the x-z-plane=projection in the y-direction in FIGS.1a-1d ) a circular, rectangular, square, oval or any desired polygonalcircumferential shape, wherein the first electrode structure 102 can beconfigured in a manner at least regionally adjoining the cutout 110 orelse completely extending around or surrounding the cutout 110.

Since the first electrode structure 102 is configured as the firstcommon (short-circuited) capacitor electrode, for example all sectionsof the first electrode structure 102 are short-circuited and connectedto the first reference potential V₁. Furthermore, for the secondelectrode structure 104, which is illustrated as continuous in FIGS.1a-1d , it holds true that for the case of a subdivision of the secondelectrode structure 104 the individual elements of the second electrodestructure 104 are short-circuited with one another and connected to thesecond reference potential V₂.

The functional principle of the moisture sensor 100 can be summarized,then, to the effect that the first and second electrode structures 102,104 are offset or spaced apart vertically (i.e., in they-direction=parallel to the x-z-plane) with respect to one another. Theactive material 106 for the moisture sensor 100, e.g., a polyimidematerial, changes its dielectric properties on the basis of the moisturelevels in the surrounding atmosphere and is arranged so as to interactwith electrical “leakage fields” between the first and second electrodestructures 102, 104. In this case, the active (=moisture-sensitive)dielectric layer element forms the moisture-dependent capacitordielectric of the measurement capacitor between the first and secondcapacitor electrodes 102, 104.

On account of the geometric arrangement of the first and secondelectrode structures 102, 104 in a vertical orientation with respect toone another (in the y-direction) with regard to the upper main surfaceregion 106-A and 108-A, respectively, the moisture sensor 100illustrated in FIGS. 1a-1d can thus also be referred to as a “vertical”moisture sensor 100.

In accordance with the exemplary embodiment of the moisture sensor 100as illustrated in FIGS. 1a-1d , it is possible to read out themeasurement capacitance between the first electrode structure 102, whichis arranged laterally adjacent to the lateral wall region 110-1 of thecutout 110 with the moisture-sensitive, dielectric layer element 106arranged therein, and the second electrode structure 104 arrangedvertically with respect to the first electrode structure and adjacent tothe bottom region 110-2 of the cutout 110.

A further possible configuration of the moisture sensor 100 inaccordance with one exemplary embodiment will now be described belowwith reference to FIGS. 2a and 2b in a basic schematic cross-sectionalillustration.

With regard to the explanations below, it is pointed out thatsubstantially the above explanations with regard to FIGS. 1a-1d areapplicable equally to the moisture sensor 100 illustrated in FIGS. 2a-2b, predominantly the modifications and/or supplementations of themoisture sensor 100 being discussed below.

As is illustrated by way of example in FIG. 2a , the moisture sensor 100comprises, over the first and second electrode structures 102, 104, themoisture-sensitive, dielectric layer element 106 and also the insulationstructure or passivation layer structure 108 having the cutout 110,having in each case a sidewall region 110-1 and a bottom region 110-2.The moisture-sensitive, dielectric layer element 106 is arranged in thecutout 110 and at least partly fills the latter. The first electrodestructure 102 is arranged adjacent to the wall region 110-1 of thecutout and at least partly in the insulation structure 108, wherein thefirst electrode structure 102 is configured as a first common, e.g.,electrically interconnected or short-circuited capacitor electrode andthe second electrode structure 104 is configured as a second commoncapacitor electrode of a measurement capacitor having a totalcapacitance C_(G) for capacitive moisture measurement.

As is illustrated in FIG. 2a , the electrode structure 104 is configuredso as, with regard to a vertical projection (in the y-direction),substantially to overlap the cutout 110 and not to overlap the firstelectrode structure 102 arranged laterally with respect thereto.

By virtue of this arrangement of the second electrode structure, in theevent of a potential difference ΔV being applied between the first andsecond electrode structures 102, 104, it is possible to compress theresultant electric field between the first and second electrodestructures 102, 104 within the cutout 110 and thus within the materialof the moisture-sensitive, dielectric layer element, such that anincreased field concentration leads to an increased permeation andinteraction with the material of the moisture-sensitive, dielectriclayer element 106. As a result, the resultant parasitic capacitanceC__(P) through the material, e.g., oxide material, of the insulationstructure 108 is reduced, and accordingly the measurement capacitanceC__(M) (C__(m1), C__(m2) and C__(m3)) through the dielectric layerelement 106 is increased, as a result of which it is possible to obtainan improved response behavior and an increased sensitivity of themoisture sensor 100 to a change in the moisture in the surroundingatmosphere.

With regard to the capacitive equivalent circuit diagram in FIG. 3d , itis pointed out that a simplified capacitive model of the moisture sensor100 is assumed there to the effect that the height h₁₁₀ of the cutouts110 is much greater than the width b₁₁₀ of the cutout 110, e.g., atleast by a factor of 5 or 10. In this case, a relatively homogenouspotential profile generated laterally across the cutout or the trench110 can be assumed. This state reduces the model to three parallelcapacitances, two capacitances C__(P) (parasitic capacitances) with theinsulation material (e.g., oxide) of the insulation structure 108 asdielectric and the intervening, central measurement capacitance C__(M)with the material, e.g., a polyimide material, of themoisture-sensitive, dielectric layer element 106.

FIG. 2b then shows a basic illustration of the resultant capacitiveequivalent circuit diagram of the measurement capacitance by way ofexample in the form of a schematic cross-sectional view of the sensorregion of the moisture sensor 100. As is evident in FIG. 2b , as aresult the resultant parasitic capacitance C__(P) can be at leastdecreased or greatly reduced, while the measurement capacitance C__(M)(C__(m1), C__(m2) and C__(m3)) can be significantly increased and asignificant increase in the sensitivity of the moisture sensor 100 canthus be obtained.

A further configuration of the moisture sensor 100 in accordance withone exemplary embodiment will now be described below with reference toFIGS. 3a -3 d.

With regard to the moisture sensor 100 described below, it is pointedout that the above explanations with regard to FIGS. 1a-1d and 2a-2b areapplicable equally to the moisture sensor 100 in FIGS. 3a-3d ,substantially the supplementations and modifications of the moisturesensor 100 being discussed below.

As is illustrated in FIG. 3a on the basis of a basic schematiccross-sectional illustration of the moisture sensor 100 in accordancewith one exemplary embodiment, the moisture sensor once again comprisesa first and a second electrode structure 102, 104, a moisture-sensitive,dielectric layer element 106, and an insulation structure 108. Theinsulation structure 108 now has for example a plurality of cutouts 110,each having a sidewall region 110-1 and a bottom region 110-2. As isillustrated in FIG. 3a , the moisture-sensitive, dielectric layerelement 106 is arranged in the cutouts 110 and at least partly fills thelatter. The first electrode structure 102 comprises for example aplurality of electrically interconnected first partial electrodestructures 102-1, 102-2, 102-3 arranged e.g., at the outer sidewallregions 110-1 and between adjacent sidewall regions 110-1 of the cutouts110 e.g., parallel to the sidewall regions 110-1 of the cutouts. Thesecond electrode structure 104 is in turn arranged (vertically) adjacentto the bottom region 110-2 of the cutouts 110 at least partly within theinsulation structure 108. Furthermore, the interconnected first partialelectrode structures 102-1, 102-2, 102-3 form the first electrodestructure 102, which is in turn configured as a first common,short-circuited (=shortened) capacitor electrode, while the secondelectrode structure 104 is configured as the second common capacitorelectrode of the measurement capacitor 102, 104 having a totalcapacitance C_(G) for capacitive moisture measurement.

In accordance with one exemplary embodiment, a respective one of thefirst partial electrode structures 102-1, 102-2, 102-3 can at leastregionally or completely surround laterally the respective one of thecutouts 110. In accordance with one exemplary embodiment, the firstpartial electrode structures 102-1, 102-2, 102-3 of the first electrodestructure 102 can also be arranged in a strip-shaped fashion betweenadjacent cutouts or trenches 110 and parallel to the sidewall regions110-1 of the cutouts or trenches 110. As is illustrated in FIG. 3a , thematerial, e.g., a polyimide material, of the moisture-sensitive,dielectric layer element 106 is arranged at least regionally between thefirst partial electrode structures 102-1, 102-2, 102-3.

As is illustrated in FIG. 3a , the first partial electrode structures102-1, 102-2, 102-3 are arranged e.g., laterally (=in the x-direction)adjacent to the wall region 110-1 of the cutouts 110 and are at leastpartly or else completely arranged in the material of the insulationstructure 108 or embedded therein. The second electrode structure 104 isthen arranged e.g., vertically (=in the y-direction) adjacent to thebottom region 110-2 of the cutout 110, and is at least partly or elsecompletely arranged in the material of the insulation structure 108 orembedded therein. Consequently, the first electrode structure 102 isconfigured as a common capacitor electrode and the second electrodestructure 104 is configured as a second common capacitor electrode of ameasurement capacitor 102, 104 having the total capacitance C_(G) forcapacitive moisture measurement, wherein the moisture-sensitive,dielectric layer element 106 is once again configured to have a relativepermittivity C_(r) dependent on the relative or absolute moisture in thesurrounding atmosphere.

Further possible configurations or implementations of the individualelements of the moisture sensor 100 will now be illustrated by way ofexample below with reference to FIGS. 3b and 3c in a basic schematiccross-sectional illustration of the moisture sensor 100.

As is illustrated in FIG. 3b , the moisture-sensitive, dielectric layerelement 106 can also be arranged above the upper surface regions 108-Aof the insulation structure 108 and completely fills the cutouts 110. Asis furthermore illustrated in FIG. 3b , once again a carrier element orsubstrate 112 can be provided.

As is evident in FIG. 3b , by way of example once again some dimensionsof individual elements of the moisture sensor 100 are then illustratedby way of example therein, wherein the dimension indications from FIG.1b can correspondingly be applied here.

FIG. 3c then illustrates a different configuration of themoisture-sensitive, dielectric layer element 106 in a basic schematiccross-sectional illustration of the moisture sensor 100. In contrast tothe illustration of the moisture-sensitive, dielectric layer element 106from FIG. 3b , in the configuration illustrated in FIG. 3c , thedielectric layer element 106 is configured as a “lining” of the cutout110, wherein the moisture-sensitive, dielectric layer element 106 coversthe wall regions 110-1 and the bottom region 110-2 of the cutouts no (atleast regionally or else completely) with a relatively uniform layerthickness d106. The dielectric layer element 106 can thus be configuredas a “conformal” coating of the sidewall regions and the bottom regions110-1, 110-2 of the cutouts no. By way of the thickness d106 of thematerial of the moisture-sensitive, dielectric layer element 106, it isthus possible to set firstly the response behavior and secondly theachievable signal-to-noise ratio of the moisture sensor 100 by providingthe largest possible interaction area of the active layer element 106with the surrounding atmosphere and furthermore the highest possiblepermeation of the active layer element 106 by the electric field linesbetween the first and second electrode structures 102, 104.

As is furthermore illustrated as optional in FIG. 3c , themoisture-sensitive, dielectric layer element 106 configured as aconformal coating can e.g., also extend onto the upper surface region108-A of the insulation structure 108. The optional region of theinsulation structure 108 on the upper surface region 108-A isillustrated in a hatched manner in FIG. 3 c.

With reference to FIG. 3d in the form of a schematic cross-sectionalview, a description will now be given below of the sensor region of themoisture sensor 100 with a basic illustration of the resultingcapacitive equivalent circuit diagram on account of the distribution ofthe electric field between the first and second electrode structures102, 104.

As is evident from FIG. 3d , the portions C__(m1), C__(m2) and C__(m3)contributing to the measurement capacitance C__(M) arise on account ofthe electric field lines passing through the moisture-sensitive,dielectric layer element 106 between the first partial electrodestructures 102-1, 102-2, 102-3 and the second electrode structure 104,while the parasitic capacitances C__(P), which do not contribute to themeasurement, represent the field lines passing between the first andsecond electrode structures 102, 104 without passing through themoisture-sensitive, dielectric layer element 106. The more field linesof the electric field E pass through the moisture-sensitive, dielectriclayer element 106 between the first and second electrode structures 102,104, the higher the portion of the measurement capacitance C__(M) andthe lower the portion of the parasitic capacitance C__(P) (i.e., theportion which does not contribute to the measurement) in the totalcapacitance C_(G) of the moisture sensor 100.

The cutouts 110 in the insulation or passivation layer structure 108 canfor example be in the shape of a trench, i.e., elongate, or have (as asectional view in the x-z-plane) a circular, rectangular, square, ovalor any desired polygon-progression-shaped circumferential shape, whereinthe first electrode structure 102 can be configured in a manner at leastregionally adjoining the cutout 110 or else completely extending aroundor surrounding the cutout 110. Since the first electrode structure 102is configured as the first common (short-circuited) capacitor electrode,for example all sections of the first electrode structure 102 areshort-circuited and connected to the first reference potential V₁.Furthermore, for the second electrode structure 104, which isillustrated as continuous in FIGS. 3a-3d , it holds true that for thecase of a subdivision of the second electrode structure 104 theindividual elements of the second electrode structure 104 areshort-circuited with one another and connected to the second referencepotential V₂.

The functional principle of the moisture sensor 100 can be summarized,then, again to the effect that the first and second electrode structures102, 104 are offset or spaced apart vertically (i.e., in they-direction=parallel to the x-z-plane) with respect to one another. Theactive material 106 for the moisture sensor 100, e.g., a polyimidematerial, changes its dielectric properties on the basis of the moisturelevels in the surrounding atmosphere and is arranged so as to interactwith electrical “leakage fields” or primarily with the vertical portionthereof between the first and second electrode structures 102, 104. Inthis case, the active (=moisture-sensitive) dielectric layer element 106forms the moisture-dependent capacitor dielectric of the measurementcapacitor between the first and second capacitor electrodes 102, 104.

On account of the geometric arrangement of the first and secondelectrode structures 102, 104 in a vertical orientation with respect toone another (in the y-direction) with regard to the upper main surfaceregion 108-A, the moisture sensor 100 illustrated in FIGS. 3a-3d canthus in turn also be referred to as a “vertical” moisture sensor.

With regard to the capacitive equivalent circuit diagram in FIG. 3d , itis pointed out that a simplified capacitive model of the moisture sensor100 is assumed there to the effect that the depth h₁₁₀ of the cutouts nois much greater than the width b₁₁₀ of the cutout 110, e.g., at least bya factor of 5 or 10. In this case, a relatively homogenous potentialprofile generated laterally across the cutout or the trench no can beassumed. This state reduces the model to three parallel capacitances,two capacitances C__(P) (parasitic capacitances) with the insulationmaterial (e.g., oxide) of the insulation structure 108 as dielectric andthe intervening, central measurement capacitance C__(M) with thematerial, e.g., a polyimide material, of the moisture-sensitive,dielectric layer element 106.

A further implementation of the moisture sensor 100 in accordance withone exemplary embodiment will now be described by way of example belowwith reference to FIGS. 4a -4 d.

With regard to the moisture sensor 100 described below, it is pointedout that the above explanations with regard to FIGS. 1a-1d, 2a-2b and3a-3d are applicable equally to the moisture sensor 100 in FIGS. 4a-4d ,substantially the supplementations and modifications of the moisturesensor 100 being discussed below.

As is illustrated by way of example in FIG. 4a in a basic schematiccross-sectional illustration of the moisture sensor 100 in accordancewith one exemplary embodiment, the moisture sensor 100 once againcomprises a first and a second electrode structure 102, 104, amoisture-sensitive, dielectric layer element 106, and an insulationstructure 108. The insulation structure 108 now has for example aplurality of cutouts 110, each having a sidewall region 110-1 and abottom region 110-2. As is illustrated in FIG. 4a , themoisture-sensitive, dielectric layer element 106 is arranged in thecutouts 110 and at least partly fills the latter. The first electrodestructure 102 comprises for example a plurality of electricallyinterconnected first partial electrode structures 102-1, 102-2, 102-3arranged e.g., at the outer sidewall regions 110-1 and between adjacentsidewall regions 110-1 of the cutouts 110 e.g., parallel to the sidewallregions 110-1 of the cutouts. The second electrode structure 104 is inturn arranged (vertically) adjacent to the bottom region 110-2 of thecutouts 110 at least partly within the insulation structure 108.Furthermore, the interconnected first partial electrode structures102-1, 102-2, 102-3 form the first electrode structure, which is in turnconfigured as a first common, short-circuited (=shortened) capacitorelectrode, while the second electrode structure 104 is configured as thesecond common capacitor electrode of the measurement capacitor 102, 104having a total capacitance C_(G) for capacitive moisture measurement.

As is illustrated by way of example in FIG. 4a , the second electrodestructure can comprise electrically interconnected second partialelectrode structures 104-1, 104-2 arranged vertically adjacent to therespective bottom region 110-2 of the cutouts 110. The second electrodestructure 104 can thus comprise patterned, short-circuited secondpartial electrode structures 104-1, 104-2 arranged for examplesubstantially complementarily to or in a manner overlapping the basicarea of the cutouts 110 with regard to a vertical projection (in they-direction). This arrangement of the first and second electrodestructures 102, 104 can serve for reducing the parasitic capacitancesC__(P).

In the moisture sensor 100 in FIG. 4a , the first and second electrodestructures 102, 104 are again arranged offset or at a distancevertically (i.e., in the y-direction) with respect to one another. Withreference to FIGS. 4b and 4c , in a basic schematic cross-sectionalillustration of the moisture sensor 100, by way of example furtherpossible configurations or implementations of the individual elements ofthe moisture sensor 100 are illustrated, as has already been describedby way of example for a continuous second electrode structure 104 inFIGS. 3b and 3 c.

On the basis of the arrangement of the second electrode structure 104 asillustrated in FIGS. 4a-4d , it is possible to reduce the parasiticlateral capacitances C__(P) with the insulation material of theinsulation structure 108 as dielectric, which are insensitive vis-à-vischanges in moisture, by increasing the width and height of the topmostmetal lines or first partial electrode structures 102-1, 102-2, 102-3.

In the configuration illustrated in FIGS. 4a-4d , the second partialelectrode structures 104-1, 104-2 of the second electrode structure 104are configured so as, with regard to a vertical projection (in they-direction), substantially to overlap the cutouts 110 and not tooverlap the first partial electrode structures 102-1, 102-2, 102-3 ofthe first electrode structure 102 that are arranged laterally withrespect thereto. The second partial electrode structures 104-1, 104-2are thus arranged in a manner overlapping vertically (in they-direction) the cutouts 110 and the moisture-sensitive, dielectriclayer element 106 arranged therein, such that substantially no overlapwith the first partial electrode structures 102-1, 102-3, 102-3 of thefirst electrode structure 102 occurs with regard to a verticalprojection (in the y-direction).

This results in a lower parasitic capacitance C__(P) and an increasedmeasurement capacitance C__(M) of the moisture sensor 100 and thus inturn to an increased sensitivity of the moisture sensor 100 vis-à-vischanges in moisture in the surrounding atmosphere.

In accordance with one exemplary embodiment, a first contact connectionarea 114 can be provided, which is electrically connected to the firstelectrode structure 102, and a second contact connection area 116 canfurthermore be present, which is connected to the second electrodestructure 104. The first and second contact connection areas 114, 116can be provided in order to read out the capacitance value C_(G) of themeasurement capacitance 102, 104 formed by the first and secondelectrode structures.

As is evident in FIG. 4b , by way of example once again some dimensionsof individual elements of the moisture sensor 100 are then illustratedby way of example therein, wherein the dimension indications from FIG.3b can correspondingly also be applied here. In FIG. 4b , merely inaddition the width b₁₀₄ of the second partial electrode structures104-1, 104-2 is indicated, wherein the width b₁₀₄ can be approximately0.5 μM to 3 μm (or 0.2 μm to 5 μm).

A further exemplary embodiment of a moisture sensor 200 in accordancewith a further exemplary embodiment will now be described below withreference to FIGS. 5a-5d . The arrangement of the moisture sensor 200 asillustrated in FIGS. 5a-5d can also be referred to as an individualelement or an elementary cell of the moisture sensor 200, wherein themoisture sensor 200 can comprise a plurality of e.g., parallel-connectedelementary cells.

As is illustrated in the basic schematic cross-sectional illustration inFIG. 5a , the moisture sensor 200 comprises a carrier element 208comprising an insulating material, a first and a second electrodestructure 202, 204 arranged at a distance from one another at thecarrier element 208, a moisture-sensitive, dielectric layer element 206at a first main surface region 208-1 of the carrier element 208 andadjacent to the first and second electrode structures 202, 204, and athird electrode structure 210 on a first main surface region 206-1 ofthe moisture-sensitive, dielectric layer element 206, such that themoisture-sensitive, dielectric layer element 206 is arranged between thethird electrode structure 210 and the first electrode structure 202 andbetween the third electrode structure 210 and the second electrodestructure 204. The carrier element 208 can furthermore optionallycomprise a substrate 212, see FIG. 5 b.

As is illustrated in FIG. 5a , the third electrode structure 210 is thusarranged at a first main surface region 206-1 of the dielectric layerelement 206, while the first and second electrode structures arearranged adjacent to the second main surface region 206-2 of thedielectric layer element 206 and in a manner spaced apart laterally (=inthe x-direction) with respect to one another.

The first electrode structure 202 is configured as a first capacitorelectrode of a measurement capacitor, wherein the second electrodestructure 204 is configured as a second capacitor electrode of themeasurement capacitor 202, 204 having the total capacitance C_(G) forcapacitive moisture measurement. The third electrode structure 210 isconfigured as a floating electrode structure.

The floating electrode structure 210 can be configured as a conductivelayer having openings 210-A having an opening diameter D₂₁₀ and webs210-B having a web width b₂₁₀, which mechanically connect and surroundthe openings 210-A, such that the moisture-sensitive, dielectric element206 is accessible to the surrounding atmosphere through said openings210-A. The floating electrode structure 210 can thus be configured as aperforated or grid-shaped conductive layer.

In the event of a potential difference ΔV being applied between thefirst and second capacitor electrodes 202, 204 of the measurementcapacitor, the floating electrode structure is configured to collect orto concentrate the electrical leakage field between the first and secondelectrode structures 202, 204. The floating electrode structure 210 cancomprise a polysilicon material or a metal, for example. Themoisture-sensitive, dielectric layer element 206 can have a relativepermittivity ε_(r) dependent on the moisture in the surroundingatmosphere. The relative permittivity ε_(r) of the dielectric layerelement 206 is thus dependent on the moisture absorbed from thesurrounding atmosphere.

In the case of the application of a potential difference ΔV asdifference between the first potential connection V₁ at the firstelectrode structure 202 and the second potential connection V₂ at thesecond electrode structure 204 and the resultant potential differencebetween the first and second capacitor electrodes 202, 204 of themeasurement capacitor, a capacitance value dependent on the moisture inthe surrounding atmosphere is able to be read out. The capacitance valueC_(G) which is able to be read out is thus dependent on the amount ofmoisture absorbed into the likewise moisture-sensitive, dielectric layerelement 206.

The first and second electrode structures 202, 204 can be embedded atleast regionally in the insulating material of the carrier element 208.The moisture-sensitive, dielectric layer element 206 can for exampleonce again comprise a polyimide material. Furthermore, a first and asecond contact connection area 214, 216 can once again be provided,wherein the first contact connection area 214 is electrically connectedto the first electrode structure 202, and wherein the second contactconnection area 216 is electrically connected to the second electrodestructure 204.

The floating electrode structure 210 can be formed by metal processingprocesses on the insulation material or polyimide material of themoisture-sensitive, dielectric layer element 206. This may for examplenecessitate subjecting the polyimide material of the moisture-sensitive,dielectric layer element 206 to a special treatment, such as e.g., athermal treatment, in order to obtain for example curing of thepolyimide material.

The moisture sensor 200 illustrated in FIGS. 5a-5d once againconstitutes a vertical component. In the design illustrated, the firstand second electrode structures 202, 204 are arranged adjacent to oneanother (side by side) with an intervening insulation material, e.g.,the insulation material of the carrier element 208. By virtue of thearrangement of the floating electrode structure (=floating contact) 210,there is then the possibility of detecting the electric field extendingfrom the first and second electrode structures 202, 204 vertically (inthe y-direction), wherein the electric field lines pass through thedielectric layer element 206 substantially vertically (in they-direction) on account of the arrangement of the floating electrodestructure 210. As a result, the interaction of the electric field lineswith the insulation material, e.g., a polyimide material, of themoisture-sensitive, dielectric layer element 206 can be significantlyincreased or maximized.

The perforated metal structure of the floating electrode structure 210makes it possible that the moisture-sensitive, dielectric layer element206 can react with the surrounding atmosphere, e.g., air, or is exposedto the surrounding atmosphere. One possible geometric configuration ofthe moisture sensor is illustrated in a 3D view by way of example inFIG. 5 b.

Since the measurement capacitance for both electrode structures 202, 204runs vertically, parasitic capacitances are substantially assigned to alateral electric field component through the insulation material, e.g.,oxide material, of the carrier element 208. This enables the resultantsensitivity of the moisture sensor 200 to be increased, whereinfurthermore an optimization of the electrode thickness and spacing canbe effected as well. The electrode thickness can be chosen to be assmall as possible, for example, in order to reduce the area of thelateral parasitic capacitances. An (as optimum as possible) electrodespacing can e.g., be calculated in advance and is dependent on variousparameters, such as e.g., electrode thickness, distance from thesubstrate, thickness of the polyimide, etc. In addition, an EM shielding(EM=electromagnetic) of the floating electrode structure 210 can betaken into consideration in this design approach. The electricalshielding can be realized e.g., by a corresponding packaging.

The moisture sensor 200 illustrated in FIG. 5c comprises a plurality ofelementary cells (cf. FIGS. 5a, 5d ) arranged in a multiply “mirrored”(e.g., at the axis M₁ or the axes M₁, M₂, M₃, . . . ) andparallel-connected manner. One such elementary cell of the moisturesensor 200 is highlighted by the dashed border in FIG. 5c . Hence inFIG. 5c the outer electrodes 202 should be regarded as the first commonelectrode 202 and the central electrode 204 should be regarded as thesecond electrode 204.

As is evident in FIG. 5c , some dimensions of individual elements of themoisture sensor 200 are then illustrated by way of example therein,wherein the illustrated dimensions or dimension ranges can also vary,e.g., by a factor of 3, in other applications.

As is furthermore illustrated in FIG. 5c , a carrier element orsubstrate 212 can be provided, wherein the first and second electrodestructures 202, 204 can be arranged as a buried electrode structure inthe insulation material of the insulation structure 208 between thecarrier element 212 and the dielectric layer element 206. The first andsecond electrode structures 202, 204 can thus also be completelyarranged in the material of the insulation structure 208 or embeddedtherein, such that the material of the insulation structure 208 can besituated between the first electrode structure 202 and the carrierelement 212 and between the second electrode structure 204 and thecarrier element 212.

As is illustrated by way of example in FIG. 5c , the first and secondelectrode structures 202, 204 can for example each have a thicknessd₂₀₂, d₂₀₄ of 330 nm±20% (or between 100 nm and 1000 nm or between 200nm and 600 nm). Furthermore, the first and second electrode structures202, 204 each have for example a width b₂₀₂, b₂₀₄ of 0.5 μm±20% (orbetween 0.1 μm and 3 μm or between 0.2 μm and 1 μm). Themoisture-sensitive, dielectric layer element 206 can have a thicknessd₂₀₆ of between 0.1 μm and 10 μm (or between 0.2 μm and 6 μm or between0.5 mm and 3 μm).

If an insulation material of the insulation structure 208 is providedbetween the first and/or the second electrode structure 202, 204 and thedielectric layer element 206, the thickness d₂₀₈ of the insulationmaterial can be 0.1 μm±20% (or between 0.01 μm and 1 μm or between 0.05μm and 0.2 μm). If an insulation material of the insulation structure208 is provided between the carrier element (substrate) 212 and thefirst and/or the second electrode structure 202, 204, the thickness d₂₁₂of the insulation material can be between 1 and 50 μm (or between 2 μmand 20 μm or between 5 μm and 10 μm).

As is illustrated by way of example in FIG. 5c , the third electrodestructure 210 can have for example in each case a thickness d₂₁₀ of 330nm f 20% (or between 100 nm and moo nm or between 200 nm and 600 nm).Furthermore, the third electrode structure 210 can for example have anopening diameter D₂₁₀ of 0.5 μm±20% (or between 0.1 μm and 3 μm orbetween 0.2 μm and 1 μm) and have a web width b₂₁₀ of 0.5 μm±20% (orbetween 0.1 μm and 3 μm or between 0.2 μm and 1 μm).

With regard to the dimensions or dimension ranges illustrated in FIG. 5c, it is pointed out that they should be assumed to be merely by way ofexample for a possible embodiment of the moisture sensor 200, wherein inaccordance with the present principle of action of the moisture sensor200, of course, other dimensions or dimension ratios can also be usedand furthermore the functionality of the moisture sensor 200 is equallymaintained.

A description will now be given below, with reference to FIG. 5d in theform of a schematic cross-sectional view, of the sensor region of themoisture sensor 200 with a basic illustration of the resulting portionsof the acting electric field or the resultant capacitive equivalentcircuit diagram.

As discussed above, the measurement capacitances C__(M) extendvertically between the first electrode structure 202 and the floatingelectrode structure 210 and between the second electrode structure 204and the floating electrode structure 210, since the electric fieldoccurring between the first and second electrode structures 202, 204 isconcentrated or short-circuited in the floating electrode structure 210.On account of the geometric arrangement, the parasitic capacitanceC__(P) present directly between the first and second electrodestructures 202, 204 is relatively small or negligible to a firstapproximation.

By virtue of this arrangement of the third electrode structure 210, inthe event of a potential difference ΔV being applied between the firstand second electrode structures 202, 204, it is possible to compress theresultant electric field between the first and second electrodestructures 202, 204 substantially within the material of themoisture-sensitive, dielectric layer element 206, such that an increasedfield concentration leads to an increased permeation and interactionwith the material of the moisture-sensitive, dielectric layer element206. As a result, the resultant parasitic capacitance C__(P) through thematerial, e.g., oxide material, of the insulation structure 208 isreduced, and accordingly the measurement capacitance C__(M) through thedielectric layer element 206 is increased, as a result of which it ispossible to obtain an improved response behavior and an increasedsensitivity of the moisture sensor 200 to a change in the moisture inthe surrounding atmosphere.

An overview of one possible production method for producing the moisturesensor 100 illustrated by way of example in FIG. 3b and FIG. 3c ,respectively, is described briefly below with reference to FIG. 6.

Firstly, in step 6-0, a substrate or the carrier element 112 isprovided.

In a step 6-1, an insulation material is applied on the substrate orcarrier element 112 for example by a CVD method.

In a further step 6-2, a metal layer (metal 1) is applied, which laterserves as the second electrode structure.

In step 6-3, an insulation material (insulator 2) is applied on thesecond electrode structure 204 once again by a CVD method, for example.

In a step 6-4, the first electrode structure 102 having the firstpartial electrode structures 102-1, 102-2, 102-3 is formed or patterned.

In a step 6-5, a further insulator material of the insulation structure108 (insulator 3) is applied by a CVD method.

In step 6-6, a planarization as far as the upper surface regions of thefirst partial electrode structures 102-1, 102-2, 102-3 is carried out.

In step 6-7, a metal passivation as final layer is applied on theplanarized surface and forms a further section of the insulationstructure (passivation layer structure) 108.

In step 6-8, the cutouts or trenches are formed, e.g. by a trench etchmethod, in the insulation structure 108 between the first partialelectrode structures 102-1, 102-2, 102-3.

In step 6-9 a, the moisture-sensitive, dielectric layer element 106 isdeposited for example conformally on the surface topography present, asa result of which the cutouts or trenches 110 are not completely filled,as is illustrated for example in the case of the moisture sensor 100from FIG. 3 c.

In an alternative step 6-9 b, the material of the moisture-sensitive,dielectric layer element 106 is deposited non-conformally, such that thecutouts 110 are completely filled, as is illustrated by way of examplein the case of the moisture sensor 100 from FIG. 3 b.

A further method for producing the moisture sensor 100 having aplurality of cutouts 110, said moisture sensor being illustrated by wayof example in FIG. 4b and FIG. 4c , respectively, will now be describedbelow with reference to FIG. 7.

The production method illustrated in FIG. 7 differs from the methodillustrated in FIG. 6 merely in step 6-2′ to the effect that the appliedmetal layer (metal 1) forming the second electrode structure 204 ispatterned in order to form the electrically interconnected,short-circuited second partial electrode structures 204-1, 204-2.

In step 6-9 a in FIG. 7, the moisture-sensitive, dielectric layerelement 106 is deposited for example conformally onto the surfacetopography present, as a result of which the cutouts or trenches no arenot completely filled, as is illustrated by way of example in the caseof the moisture sensor 100 from FIG. 4 c.

In an alternative step 6-9 b in FIG. 7, the material of themoisture-sensitive, dielectric layer element 106 is depositednon-conformally, such that the cutouts no are completely filled, as isillustrated by way of example in the case of the moisture sensor 100from FIG. 4 b.

One possible method for producing the moisture sensor 200 illustrated inFIGS. 5a-5d in accordance with a further exemplary embodiment will nowbe described below with reference to FIG. 8.

As is illustrated in FIG. 8, firstly in a step 8-0 the carrier element212 is provided. An insulation material (insulator 1) of the insulationstructure 208 is applied on the carrier element 212 by a CVD method.

In step 8-2, a metal layer (metal 1) is applied in a patterned manner inorder to form the first and second electrode structures arranged in amanner spaced apart from one another at the carrier element 212.

In step 8-3, a further insulator material (insulator 2) is applied forexample once again by a CVD method, and in step 8-4 is planarized inorder to form a further section of the carrier element 212.

In step 8-5, a metal passivation layer is applied in order to cover thefirst and second electrode structures and to form a further section ofthe carrier element.

In step 8-6, the moisture-sensitive, dielectric layer element 206 isapplied, e.g., by a polyimide deposition.

In step 8-7, finally, the third electrode structure is applied as afloating electrode structure, which is configured as a conductive,perforated or grid-shaped layer, as is illustrated for example in thecase of the moisture sensor 200 from FIG. 5 c.

In accordance with one exemplary embodiment, a moisture sensor 100comprises a first and a second electrode structure 102, 104, amoisture-sensitive, dielectric layer element 106, and an insulationstructure 108 having a cutout 110 having a sidewall region 110-1 and abottom region 110-2. The moisture-sensitive, dielectric layer element106 is arranged in the cutout 110 and at least partly fills the latter,wherein the first electrode structure 102 is arranged adjacent to thewall region 110-1 of the cutout 110 at least partly in the insulationstructure 108, wherein the second electrode structure 104 is arrangedadjacent to the bottom region 110-2 of the cutout 110 at least partly inthe insulation structure 108, and wherein the first electrode structure102 is configured as a first common capacitor electrode and the secondelectrode structure 104 is configured as a second common capacitorelectrode of a measurement capacitor 102, 104 for capacitive moisturemeasurement.

In accordance with one exemplary embodiment, the moisture-sensitive,dielectric layer element 106 is configured to be effective at leastregionally as a capacitor dielectric of the measurement capacitorbetween the first and second capacitor electrodes 102, 104.

In accordance with one exemplary embodiment, the moisture-sensitive,dielectric layer element 106 has a relative permittivity dependent onthe moisture in the surrounding atmosphere.

In accordance with one exemplary embodiment, in the event of a potentialdifference ΔV being present between the first and second capacitorelectrodes 102, 104 of the measurement capacitor, a capacitance valuedependent on the moisture in the surrounding atmosphere is able to beread out.

In accordance with one exemplary embodiment, the moisture sensor 100furthermore comprises a carrier element 112, wherein the secondelectrode structure 104 arranged in a manner adjoining the bottom region110-2 of the cutout 110 is arranged between the insulation material ofthe insulation structure 108 and the carrier element 112.

In accordance with one exemplary embodiment, the second electrodestructure 104 is arranged as a buried electrode structure between thecarrier element 112 and the insulation structure 108.

In accordance with one exemplary embodiment, the carrier element 112comprises a substrate or a metal layer.

In accordance with one exemplary embodiment, the insulation structure108 comprises an insulation material, wherein the first and secondelectrode structures 102, 104 are embedded at least regionally in theinsulation material of the insulation structure 108.

In accordance with one exemplary embodiment, the moisture sensor 100comprises a plurality of cutouts 110 in the insulation structure 108,each of said cutouts having a sidewall region 110-1 and a bottom region110-2.

In accordance with one exemplary embodiment, the first electrodestructure 102 comprises a plurality of electrically interconnected firstpartial electrode structures 102-1, 102-2, 102-3 arranged parallel tothe sidewall regions 110-1 of the cutouts 110.

In accordance with one exemplary embodiment, one of the first partialelectrode structures 102-1, 102-2, 102-3 respectively surrounds one ofthe cutouts 110.

In accordance with one exemplary embodiment, the first electrodestructure 102 is arranged in a strip-shaped fashion between adjacentcutouts 110 and parallel to the sidewall regions 110-1 of the cutouts110.

In accordance with one exemplary embodiment, a polyimide material isarranged between the first partial electrode structures 102-1, 102-2,102-3.

In accordance with one exemplary embodiment, the second electrodestructure 104 comprises electrically interconnected second partialelectrode structures 104-1, 104-2 arranged vertically adjacent to thebottom region 110-2 of the cutouts 110.

In accordance with one exemplary embodiment, the moisture-sensitive,dielectric layer element 106 comprises a polyimide material.

In accordance with one exemplary embodiment, the moisture-sensitive,dielectric layer element completely covers the sidewall regions 110-1and the bottom regions 110-2 of the cutouts 110 and/or completely fillsthe cutouts 110.

In accordance with one exemplary embodiment, the moisture sensor 100comprises a first contact connection area 114, which is connected to thefirst electrode structure 102, and a second contact connection area 116,which is connected to the second electrode structure 104.

In accordance with one exemplary embodiment, a moisture sensor 200comprises a carrier element 208 comprising an insulating material, afirst and a second electrode structure 202, 204 arranged at a distancefrom one another at the carrier element 208, a moisture-sensitive,dielectric layer element 206 at a first main surface region 208-1 of thecarrier element 208 and adjacent to the first and second electrodestructures 202, 204, and a third electrode structure 210 on a first mainsurface region 206-1 of the moisture-sensitive, dielectric layer element206, such that the moisture-sensitive, dielectric layer element 206 isarranged between the third electrode structure 210 and the firstelectrode structure 202 and between the third electrode structure 210and the second electrode structure 204. In this case, the firstelectrode structure 202 is configured as a first capacitor electrode andthe second electrode structure 204 is configured as a second capacitorelectrode of a measurement capacitor 202, 204 for capacitive moisturemeasurement, wherein the third electrode structure 210 is configured asa floating electrode structure.

In accordance with one exemplary embodiment, the floating electrodestructure 210 comprises a conductive layer having openings 210-A, suchthat the moisture-sensitive, dielectric layer element 206 is accessibleto the surrounding atmosphere through the openings 210-A.

In accordance with one exemplary embodiment, in the event of a potentialdifference ΔV being present between the first and second capacitorelectrodes 202, 204 of the measurement capacitor, the floating electrodestructure 210 is configured for collecting the electrical leakage fieldbetween the first and second electrode structures 202, 204.

In accordance with one exemplary embodiment, the floating electrodestructure 210 comprises an electrically conductive material.

In accordance with one exemplary embodiment, the moisture-sensitive,dielectric layer element 206 has a relative permittivity dependent onthe moisture in the surrounding atmosphere.

In accordance with one exemplary embodiment, in the event of a potentialdifference being present between the first and second capacitorelectrodes 202, 204 of the measurement capacitor, a capacitance valuedependent on the moisture in the surrounding atmosphere is able to beread out.

In accordance with one exemplary embodiment, the first and secondelectrode structures 202, 204 are embedded at least regionally in theinsulating material of the carrier element 208.

In accordance with one exemplary embodiment, the moisture-sensitive,dielectric layer element 206 comprises a polyimide material.

In accordance with one exemplary embodiment, the moisture sensor 200comprises a first contact connection area 214, which is connected to thefirst electrode structure 202, and a second contact connection area 216,which is connected to the second electrode structure 204.

In accordance with one exemplary embodiment, the moisture-sensitive,dielectric layer element 206 is configured to be effective at leastregionally as a capacitor dielectric of the measurement capacitor.

Although some aspects of the present disclosure have been described asfeatures in the context of a device, it is clear that such a descriptioncan likewise be regarded as a description of corresponding methodfeatures. Although some aspects have been described as features inassociation with a method, it is clear that such a description can alsobe regarded as a description of corresponding features of a device or ofthe functionality of a device.

In the detailed description above, in some instances different featureshave been grouped together in examples in order to rationalize thedisclosure. This type of disclosure ought not to be interpreted as theintention that the claimed examples have more features than areexpressly indicated in each claim. Rather, as represented by thefollowing claims, the subject matter can reside in fewer than allfeatures of an individual example disclosed. Consequently, the claimsthat follow are hereby incorporated in the detailed description, whereineach claim can be representative of a dedicated separate example. Whileeach claim can be representative of a dedicated separate example, itshould be noted that although dependent claims refer back in the claimsto a specific combination with one or more other claims, other examplescan also comprise a combination of dependent claims with the subjectmatter of any other dependent claim or a combination of each featurewith other dependent or independent claims. Such combinations shall beencompassed, unless an explanation is given that a specific combinationis not intended. Furthermore, the intention is for a combination offeatures of a claim with any other independent claim also to beencompassed, even if this claim is not directly dependent on theindependent claim.

Although specific exemplary embodiments have been illustrated anddescribed herein, it will be apparent to a person skilled in the artthat a multiplicity of alternative and/or equivalent implementations canbe substituted for the specific exemplary embodiments shown andillustrated there, without departing from the subject matter of thepresent application. This application text is intended to cover alladaptations and variations of the specific exemplary embodimentsdiscussed and described herein. Therefore, the present subject matter ofthe application is limited only by the wording of the claims and theequivalent embodiments thereof.

What is claimed is:
 1. A moisture sensor comprising: a first and asecond electrode structure; a moisture-sensitive, dielectric layerelement; and an insulation structure having a cutout having a sidewallregion and a bottom region, wherein the moisture-sensitive, dielectriclayer element is arranged in the cutout and at least partly fills thecutout, wherein the first electrode structure is arranged adjacent to awall region of the cutout at least partly in the insulation structure,wherein the second electrode structure is arranged adjacent to thebottom region of the cutout at least partly in the insulation structure,wherein the first electrode structure is configured as a first commoncapacitor electrode and the second electrode structure is configured asa second common capacitor electrode of a measurement capacitor forcapacitive moisture measurement, and wherein an upper surface of thefirst electrode structure, the moisture-sensitive, dielectric layerelement, and the insulation structure are coplanar.
 2. The moisturesensor as claimed in claim 1, wherein the moisture-sensitive, dielectriclayer element is configured to be effective at least regionally as acapacitor dielectric of the measurement capacitor between the firstcommon capacitor electrode and the second common capacitor electrode. 3.The moisture sensor as claimed in claim 1, wherein themoisture-sensitive, dielectric layer element has a relative permittivitydependent on the moisture in a surrounding atmosphere.
 4. The moisturesensor as claimed in claim 1, wherein a potential difference is presentbetween the first common capacitor electrode and the second commoncapacitor electrode of the measurement capacitor, and a capacitancevalue dependent on the moisture in a surrounding atmosphere is able tobe read out.
 5. The moisture sensor as claimed in claim 1, furthercomprising: a carrier element, wherein the second electrode structurearranged in a manner adjoining the bottom region of the cutout isarranged between insulation material of the insulation structure and thecarrier element.
 6. The moisture sensor as claimed in claim 5, whereinthe second electrode structure is arranged as a buried electrodestructure between the carrier element and the insulation structure. 7.The moisture sensor as claimed in claim 5, wherein the carrier elementcomprises a substrate or a metal layer.
 8. The moisture sensor asclaimed in claim 1, wherein the insulation structure comprises aninsulation material, wherein the first and second electrode structuresare embedded at least regionally in insulation material of theinsulation structure.
 9. The moisture sensor as claimed in claim 8,wherein the first electrode structure comprises a plurality ofelectrically interconnected first partial electrode structures arrangedparallel to the sidewall regions of the cutouts.
 10. The moisture sensoras claimed in claim 9, wherein one of the first partial electrodestructures respectively surrounds one of the cutouts.
 11. The moisturesensor as claimed in claim 9, wherein a polyimide material is arrangedbetween the first partial electrode structures.
 12. The moisture sensoras claimed in claim 1, further comprising: a plurality of cutouts in theinsulation structure, each of said cutouts having a sidewall region anda bottom region.
 13. The moisture sensor as claimed in claim 12, whereinthe first electrode structure is arranged in a strip-shaped fashionbetween adjacent cutouts and parallel to the sidewall regions of thecutouts.
 14. The moisture sensor as claimed in claim 12, wherein thesecond electrode structure comprises electrically interconnected secondpartial electrode structures arranged vertically adjacent to the bottomregion of the cutouts.
 15. The moisture sensor as claimed in claim 1,wherein the moisture-sensitive, dielectric layer element comprises apolyimide material.
 16. The moisture sensor as claimed in claim 1,wherein the moisture-sensitive, dielectric layer element completelycovers the sidewall regions and the bottom regions of the cutouts and/orcompletely fills the cutouts.
 17. The moisture sensor as claimed inclaim 1, further comprising: a first contact connection area, which isconnected to the first electrode structure, and a second contactconnection area, which is connected to the second electrode structure.